Monochloroacetylene (MCA) is a toxic, detonable and volatile compound produced as a minor byproduct in the dehydrochlorination of 1,1,2-trichloroethane to form 1,1-dichloroethylene product. The MCA content in the chlorohydrocarbon product is dependent on the type of dehydrochlorination process, for example, thermal dehydrochlorination products typically have MCA levels in excess of 10 p.p.m., whereas alkaline dehydrochlorination products typically have MCA levels in excess of 200 p.p.m.
Distillative techniques have been used to separate the lower boiling MCA from the 1,1-dichloroethylene product but in large scale industrial operations the temporary accumulation of large quantities of MCA and its subsequent disposal constitute a problem. In addition, it is recognized practice to avoid the presence of copper in 1,1-dichloroethylene product processing systems since copper may result in the formation of highly explosive acetylides.
Nieuwland-type catalyst solutions containing copper salts and halogen acids have been used to prepare a variety of chlorinated hydrocarbon derivatives using acetylene as the principal reactant (see U.S. Pat. No. 2,915,565 issued to A. Jacobowsky et al and U.S. Pat. No. 3,197,515 issued to P. Chassaing et al).